The Security Mentor

There are a few free antivirus packages. They're usually not the absolute best, but often beat the performance of some of the famous commercial offerings.

That's the way it turned out when a Watchguard reader submitted an infected file to a web site, VirusTotal, which hosts 27 virus scanners and applies them all to the file you upload. One commercial product, which has been resting on its marketing budget for years while professionals gradually gave up on it, completely failed. The commercial product I use on my own machine, "Nod32", caught it just fine. And so did ClamAV, a free program from the Linux world!